Much dental work necessarily involves various kinds and amounts of tooth reduction. Examples, for instance, include the preparation of proximal boxes or outline forms for such materials as amalgam, cast or compacted gold, and sometimes composite restorative filling materials. Large carious lesions dictate the outline form of the cavity, but it is the small or moderate lesion on the proximal surface of the tooth that taxes the skill of the operator (the Class II lesion). Also requiring a great deal of skill on the part of the operator is the prepartion of two or more proximal boxes with a common path of insertion for the fabrication of the cast gold restoration. There is a large number of various jigs, guides, and templates which engage the teeth for dental work of assorted kinds, see for example, U.S. Pat. Nos. 2,224,264; 2,634,501; 2,675,615; 3,011,259; 3,063,149; 3,073,561; 3,254,413; and 3,839,797. Yet typically the practice is to cut proximal outline forms or boxes almost "free hand", so to speak, a laborious and time consuming operation and one which causes much stress on the part of the operator to achieve a consistently accurate result. Depsite this fact and the profusion of existing jigs and templates, there is and has been nothing, so far as is known, directed specifically to all aspects of the preparation of proximal outline forms or boxes. This, therefore, is the primary object of the present invention.